Structure-Energy Relationships of Lithium Enolate Aggregates

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This grant in Organic and Macromolecular Chemistry provides support for the research of Dr. Edward Arnett, Duke University. The work is focused on the structure-energy relationships which characterize the aggregation and reactivity of organic anions in solution. Understanding such relationships is essential for a complete construction of the interactions between reactants and solvents in solution. The following processes will be studied: (1) the energies for a number of fundamental processes such as heats of interaction of lithium cation with neutral ligands such as ethers, esters, ketones, aldehydes, and amines and with enolate, phenolate and alkoxide ions; (2) heats of reaction of direct relevance to the important reactions of lithium enolates such as the aldol and Michael condensations; (3) the degrees of aggregation for selected enolate ions in a spectrum of solvents of varied polarity --cyclohexane, benzene, dioxane, DMSO and sulfolane-- by freezing point depression (such results will be related to x-ray crystal structures, heteronuclear NMR, heats of complexing and, in favorable cases, to kinetic analysis of alkylation or aldol reactions); (4) equilibration of carbocations, carbanions, and radicals where thermodynamics and kinetics for single electron transfer may be compared directly with coordination (two electron transfer).